U.S. patent application number 13/008219 was filed with the patent office on 2011-10-06 for evaporator unit.
This patent application is currently assigned to DENSO International America, Inc.. Invention is credited to Bradley Brodie, Kwangtaek Hong, Bryan Styles.
Application Number | 20110239697 13/008219 |
Document ID | / |
Family ID | 44708038 |
Filed Date | 2011-10-06 |
United States Patent
Application |
20110239697 |
Kind Code |
A1 |
Styles; Bryan ; et
al. |
October 6, 2011 |
EVAPORATOR UNIT
Abstract
An evaporator unit comprising an evaporator, an internal heat
exchanger defining a high pressure flow passage and a low pressure
flow passage, an expansion device connected downstream of the high
pressure flow passage of the internal heat exchanger and upstream
of the evaporator. The internal heat exchanger is attached to the
evaporator. With the above structure, the internal heat exchanger
can utilize the remaining cooling capability of the refrigerant
exiting from the evaporator for its greatest benefit.
Inventors: |
Styles; Bryan; (Livonia,
MI) ; Hong; Kwangtaek; (Ann Arbor, MI) ;
Brodie; Bradley; (Milford, MI) |
Assignee: |
DENSO International America,
Inc.
Southfield
MI
DENSO Corporation
Kariya-shi
|
Family ID: |
44708038 |
Appl. No.: |
13/008219 |
Filed: |
January 18, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61319778 |
Mar 31, 2010 |
|
|
|
Current U.S.
Class: |
62/524 |
Current CPC
Class: |
F25B 39/022 20130101;
F25B 2500/18 20130101; F25B 40/00 20130101; F28D 1/0461 20130101;
F28D 7/0025 20130101 |
Class at
Publication: |
62/524 |
International
Class: |
F25B 39/02 20060101
F25B039/02 |
Claims
1. An evaporator unit comprising: an evaporator defining a
refrigerant flow passage, an inlet port of the refrigerant flow
passage and an outlet port of the refrigerant flow passage; an
internal heat exchanger defining a high pressure flow passage into
which high pressure refrigerant flows, and a low pressure flow
passage into which low pressure refrigerant from the outlet port of
the evaporator flows; and an expansion device connected downstream
of the high pressure flow passage of the internal heat exchanger
and upstream of the inlet port of the evaporator, wherein the
internal heat exchanger and the evaporator are integrated to create
one assembly.
2. The evaporator unit according to claim 1, wherein: the
evaporator comprises a first tank, a second tank, and a plurality
of tubes which interconnect the first tank and the second tank; the
plurality of tubes define a heat exchange surface along their
longitudinal length; the internal heat exchanger is attached to a
side surface of the evaporator, the side surface of the evaporator
is perpendicular to the heat exchange surface; and the internal
heat exchanger resides over the first tank and the second tank.
3. The evaporator unit according to claim 2, wherein both the inlet
port and the outlet port of the refrigerant flow passage are
disposed on the side surface of the evaporator.
4. The evaporator unit according to claim 3, wherein the inlet port
and the outlet port are both disposed toward the first tank.
5. The evaporator unit according to claim 1, wherein: the expansion
device is a thermostatic expansion device having a temperature
sensing element and a diaphragm, and the temperature sensing
element is attached to the outlet port of the low pressure flow
passage of the internal heat exchanger.
6. The evaporator unit according to claim 5, wherein the
thermostatic expansion device further defines, a chamber
accommodating the diaphragm, and means for connecting the
temperature sensing element and the chamber.
7. The evaporator unit according to claim 6, wherein the evaporator
unit further comprises a means for insulating heat between the
internal heat exchanger and the means for connecting the
temperature sensing element and the chamber.
8. The evaporator unit according to claim 1, wherein the internal
heat exchanger further comprises a connecting tank which is divided
into a first connecting space and a second connecting space by a
division wall, wherein: the first connecting space communicates
with the high pressure flow passage, the second connecting space
communicates with the low pressure flow passage, and one of the
high pressure flow passage and the low pressure flow passage
penetrates the other's connecting space and the division wall to
reach its respective connecting space.
9. A heat exchanger comprising: a first refrigerant flow passage; a
second refrigerant flow passage disposed adjacent to the first
refrigerant flow passage; a connecting tank which is divided into a
first connecting space and a second connecting space by a division
wall, wherein: the first connecting tank space communicates with
the first refrigerant flow passage; the second connecting tank
space communicates with the second refrigerant flow passage, and
the second refrigerant flow passage penetrates the first connecting
space and the division wall to reach the second connecting
space.
10. An evaporator unit comprising: an evaporator defining a
refrigerant flow passage, an inlet port of the refrigerant flow
passage and an outlet port of the refrigerant flow passage; an
internal heat exchanger defining a high pressure flow passage into
which high pressure refrigerant flows, and a low pressure flow
passage into which low pressure refrigerant from the outlet port of
the evaporator flows; and an expansion device connected downstream
of the high pressure flow passage of the internal heat exchanger
and upstream of the inlet port of the evaporator, wherein: the
expansion device is a thermostatic expansion device having a
temperature sensing element and a diaphragm, and the temperature
sensing element is attached to the outlet side of the low pressure
flow passage of the internal heat exchanger.
11. The evaporator unit according to claim 1, wherein: the
expansion device is an electronic expansion device controlled by an
electronic control device, and the electronic control device
controls the electronic expansion device based on refrigerant
temperature.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 61/319,778, filed on Mar. 31, 2010. The
entire disclosure of the above application is incorporated herein
by reference.
FIELD
[0002] The present disclosure relates to an evaporator unit, which
is applied to a vapor compression cycle having an internal heat
exchanger.
BACKGROUND
[0003] This section provides background information related to the
present disclosure, which is not necessarily prior art. FIG. 19
depicts a schematic view of a vapor compression cycle, such as an
air conditioning cycle or refrigeration cycle, in accordance with
the prior art. More specifically, a compressor 2 may compress a
working fluid such as a refrigerant into a high pressure gas and
force it into a condenser 4, where heat is removed from the gas
phase refrigerant in an attempt to further lower the temperature of
the compressed refrigerant. The gas phase refrigerant is condensed
to a liquid phase refrigerant, exits condenser 4 and proceeds to
pass through a high pressure flow passage 6 of an internal heat
exchanger 7 where the liquid phase refrigerant is further cooled by
using the cool refrigerant that exits from the evaporator 10. Upon
passing through the internal heat exchanger 7, the compressed
liquid refrigerant passes through a thermostatic expansion valve
("TXV") 8 that controls the amount of refrigerant flow into an
evaporator 10 thereby controlling the superheat at the outlet of
evaporator 10. In controlling the amount of superheat exiting
evaporator 10, a temperature detecting device 12 may be used to
adjust an amount of refrigerant entering evaporator 10. The
temperature detecting device 12 is commonly integrated into the
structure of TXV 8. Upon passing temperature detecting device 12,
refrigerant then passes into a low pressure flow passage 14 of the
internal heat exchanger 7. The high pressure flow passage 6 is
located next to the low pressure flow passage 14, such that
refrigerant passing through the high pressure flow passage 6 expels
heat that is absorbed by refrigerant passing through the low
pressure flow passage 14. Upon exiting the low pressure flow
passage 14, refrigerant enters compressor 2 where it is again
compressed.
[0004] The above vapor compression cycle has proven satisfactory
for its intended purpose, but a need exists for improvement of its
efficiency.
SUMMARY
[0005] In order to improve efficiency, the present disclosure
describes an evaporator unit comprising an evaporator, an internal
heat exchanger defining a high pressure flow passage, and low
pressure flow passage, an expansion device connected downstream
side of the high pressure flow passage of the internal heat
exchanger and upstream side of the evaporator. The internal heat
exchanger and the evaporator maybe integrated to create one
assembly. With the above structure, the internal heat exchanger may
utilize the remaining cooling capability of the refrigerant just
exiting from the evaporator as much as possible. In contrast, if
the internal heat exchanger is disposed apart from the evaporator,
the refrigerant exiting from the evaporator would absorb heat from
the ambient atmosphere, and the internal heat exchanger could not
utilize the cooling capability as much as it could. So, the
efficiency of the entire vapor compression cycle is improved by the
structure described above, relative to vapor compression cycles
known in the art.
[0006] In another aspect of this disclosure, the evaporator may
employ a first tank, a second tank, and a plurality of tubes which
interconnect the first tank and the second tank. The plurality of
tubes may define a heat exchange surface along their longitudinal
side, and the internal heat exchanger may be attached to a side
surface of the evaporator. The evaporator side surface may be
perpendicular to the heat exchange surface. The internal heat
exchanger may reside over the first and second tanks. With the
above structure, the evaporator unit is compact.
[0007] In another aspect of this disclosure, both the inlet port
and the outlet port of the refrigerant flow passage may be disposed
on the side surface of the evaporator. With the above structure,
the internal heat exchanger can directly communicate with the inlet
port and the outlet port.
[0008] In another aspect of this disclosure, the inlet port and the
outlet port may both be disposed on the first tank. With the above
structure, the internal heat exchanger can make the high pressure
flow direction opposite from the low pressure flow direction.
[0009] In another aspect of this disclosure, the expansion device
may be a thermostatic expansion device having a temperature sensing
element and a diaphragm. The temperature sensing element may be
attached to the outlet port. With the above structure, the
evaporator unit may control the phase of the refrigerant just
before the compressor.
[0010] In another aspect of this disclosure, the thermostatic
expansion device may employ a chamber accommodating the diaphragm
and a means for connecting the temperature sensing element and the
chamber. The evaporator unit may further employ a means for
insulating heat between the internal heat exchanger and the means
for connecting the temperature sensing element and the chamber.
With the above structure, the evaporator unit may detect the
temperature of the refrigerant more exactly.
[0011] In another aspect of this disclosure, the internal heat
exchanger may employ a connecting tank which may be divided into a
first connecting space and a second connecting space by a division
wall. Said first connecting space may communicate with the high
pressure flow passage, the second connecting space may communicate
with the low pressure flow passage, and one of the high pressure
flow passage and low pressure flow passage, penetrates the other's
connecting space and the division wall to reach its respective
connecting space. With the above structure, the internal heat
exchanger can locate high pressure flow passage more close to the
low pressure flow passage using a simple structure.
[0012] Further areas of applicability will become apparent from the
description provided herein. It should be understood that the
description and specific examples are intended for purposes of
illustration only and are not intended to limit the scope of the
present disclosure.
DRAWINGS
[0013] The drawings described herein are for illustrative purposes
only of selected embodiments and not all possible implementations,
and are not intended to limit the scope of the present
disclosure.
[0014] FIG. 1 is a side view of a vehicle depicting a location of
an engine and a vapor compression cycle in accordance with the
present disclosure.
[0015] FIG. 2 is a schematic view of a vapor compression cycle in
accordance with a first embodiment.
[0016] FIG. 3 is a front view of an evaporator unit, including an
evaporator, an internal heat exchanger, and TXV in accordance with
the first embodiment.
[0017] FIG. 4 is a side view of an internal heat exchanger and TXV
in accordance with the first embodiment.
[0018] FIG. 5 is a side view of the internal heat exchanger in
accordance with the first embodiment.
[0019] FIG. 6 is an enlarged front view of the internal heat
exchanger in accordance with the first embodiment.
[0020] FIG. 7 is a graph of pressure verses enthalpy versus
temperature in accordance with the first embodiment.
[0021] FIG. 8 is an exploded view of an evaporator unit in
accordance with a second embodiment.
[0022] FIG. 9 is a cross sectional view of the internal heat
exchanger and TXV in accordance with the second embodiment.
[0023] FIG. 10 is an exploded view of an evaporator unit in
accordance with a third embodiment.
[0024] FIG. 11 is a cross sectional view of the internal heat
exchanger and TXV in accordance with the third embodiment.
[0025] FIG. 12 is a side view of the internal heat exchanger and
TXV in accordance with the third embodiment.
[0026] FIG. 13 is a front view of the evaporator unit in accordance
with the third embodiment.
[0027] FIG. 14 is a cross sectional view of the internal heat
exchanger and TXV in accordance with a fourth embodiment.
[0028] FIG. 15 is a cross sectional view of the internal heat
exchanger and TXV in accordance with a fifth embodiment.
[0029] FIG. 16 is an exploded view of the evaporator unit in
accordance with a sixth embodiment.
[0030] FIG. 17 is a cross sectional view of the internal heat
exchanger and TXV in accordance with the sixth embodiment.
[0031] FIG. 18 is an exploded view of the evaporator unit in
accordance with a seventh embodiment.
[0032] FIG. 19 is a schematic view of a vapor compression cycle in
accordance with the prior art.
[0033] Corresponding reference numerals indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0034] With reference to FIGS. 1-7 of the accompanying drawings,
details of the first embodiment of the present disclosure will be
described. FIG. 1 is a side view of vehicle 20 depicting a location
of an engine 22 and a vapor compression cycle 24, such as an
air-conditioning cycle in accordance with the present disclosure.
The air-conditioning cycle also extends back into the dash-covering
area between the engine compartment and vehicle cabin. Turning now
to FIG. 2, vapor compression cycle 24 may begin at a compressor 28
where a refrigerant such as, but not limited to, R134a, R1234yf or
R-744 may be compressed into a high temperature, super-heated,
vapor state. In the case of a subcritical refrigerant, the
super-heated, vapor refrigerant is then forced into line 30 en
route to a condenser 32. Upon passing into condenser 32,
refrigerant expels or relinquishes heat to air 34 flowing through a
core of condenser 32. During relinquishment of heat to air 34,
compressed refrigerant maintains pressure but changes phase to a
dual phase, liquid and vapor, refrigerant. Upon exiting condenser
32, the refrigerant may become partially or completely liquid. The
refrigerant may then be forced through line 36 before passing into
high pressure flow passage 38, which will be discussed shortly.
Upon passing out of high pressure flow passage 38, liquid
refrigerant then moves into line 40 and subsequently a thermostatic
expansion valve ("TXV") 42 or may be passed from high pressure flow
passage 38 to TXV 42. Upon passing out of TXV 42, the previously
highly compressed refrigerant expands into line 44 or be passed
directly from TXV 42 into evaporator 46, having a core 62. Such
expansion upon the refrigerant passing out of the TXV 42 causes a
relatively large drop in pressure and temperature. Upon passing
into evaporator 46, the refrigerant may again be in a dual, liquid
and vapor phase or state, and is heated by air 47 passing through
evaporator 46. Upon passing out of evaporator 46, vaporous
refrigerant may pass immediately into low pressure flow passage 48
which, as will be explained later, is integrated with high pressure
flow passage 38 and evaporator 46. High pressure flow passage 38
and low pressure flow passage 48 constitute an internal heat
exchanger 64. Heat exchanger 64 and evaporator 46 are integrated to
create one assembly (i.e. evaporator unit 60). More specifically,
internal heat exchanger 64 is attached to a mounting portion 65 of
evaporator 46. Mounting portion 65 is provided by one of a side
wall 61 of evaporator 46. Side wall 61 is disposed adjacent to core
62. Upon immediately passing out of internal heat exchanger 64 and
into line 54, a temperature of refrigerant is measured using a
temperature-sensing device 52, which communicates via a
communication line 56 with TXV 42. Temperature-sensing device 52
may also be attached or connected to an outlet 68, as depicted in
FIG. 5. Vaporous refrigerant then passes from line 54 into
compressor 28, which completes a vapor-compression cycle and
permits the refrigerant to undergo another vapor compression
cycle.
[0035] In accordance with the present disclosure, FIG. 3 depicts a
single, unitary evaporator unit 60. The internal heat exchanger 64
in this embodiment may be a micro channel internal heat exchanger
64.
[0036] FIGS. 4-6 depict enlarged views of internal heat exchanger
64. More specifically, FIG. 4 is a side view depicting an internal
heat exchanger inlet 66 and an internal heat exchanger outlet 68.
Internal heat exchanger inlet 66 communicates with high pressure
flow passage 38. Internal heat exchanger outlet 68 communicates
with low pressure flow passage 48. More specifically, inlet 66 may
be an inlet that receives relatively high-pressure liquid
refrigerant to flow inside of tubes 70, 72, 74, 76 in an upward
direction in accordance with arrow 78 from a bottom tank 80 of
internal heat exchanger 64 to a top tank 82 of internal heat
exchanger 64. Tubes 70, 72, 74 constitute the high pressure flow
passage 38. It should be understood that terms such as upward and
downward are relative to ground upon which vehicle 20 rests when
internal heat exchanger 64 is installed in a vehicle, such as
vehicle 20 for example. Upon reaching top tank 82 of internal heat
exchanger 64, relatively high-pressure refrigerant passes into TXV
42 to permit expansion of high-pressure refrigerant into evaporator
core 62. Upon passing from TXV 42, the expanded refrigerant passes
through evaporator core 62 and absorbs heat from the outside air
47. Decompressed or expanded refrigerant again passes into internal
heat exchanger 64 at return inlet 86 at a top tank 82 of internal
heat exchanger 64. Upon re-entering at top tank 82 at return inlet
86, decompressed refrigerant passes downward through internal heat
exchanger in accordance with arrow 88 by passing through tubes 90,
92, 94, and reaches outlet 68. Tubes 90, 92, 94 constitute low
pressure flow passage 48. The refrigerant passes from outlet 68
into line 54, and upon flowing through line 54, refrigerant reaches
compressor 28. The tubes 70, 72, 74 physically touch to the tubes
90, 92, 94. In this embodiment, the high pressure flow passage 38
comprises 4 tubes, and the low pressure flow passage 48 comprises 3
tubes. Alternatively, due to the relative refrigerant densities,
the low pressure flow passage 48 may comprise 4 tubes, and the high
pressure flow passage 38 may comprise 3 tubes.
[0037] With reference to FIG. 3, an advantage of the present
disclosure is that evaporator unit 60 allows vapor compression
cycle 24 to use the cooling capacity of the refrigerant just
flowing out from evaporator 46 as much as it can. So, with
evaporator unit 60 in this embodiment, total fuel efficiency is
improved, relative to the conventional vapor compression cycle
depicted in FIG. 19. With reference to FIG. 4, another advantage of
the present disclosure is that when liquid refrigerant exits low
pressure flow passage 48 at top tank 82 and enters TXV 42, it will
have benefited from being further cooled by low-pressure
refrigerant that is lower in temperature and that enters internal
heat exchanger 64 at return inlet 86. Such entering refrigerant
subsequently moves downward through internal heat exchanger tubes
90-94 to absorb heat form the upwardly moving, higher pressure,
higher temperature refrigerant moving through tubes 70-76 that is
exiting internal heat exchanger 64 at top tank 82, as depicted with
FIGS. 4 and 6. When exiting refrigerant is further heated in such a
manner, the refrigerant that is returned to the compressor 28 may
be in a superheated, vaporous state which is controlled by TXV 42
using the temperature sensing device 52 such as temperature sensing
bulb 52, which improves compressor efficiency and may extend the
useful life of compressor 28. Other advantages of the present
disclosure are the improved packaging of the vapor-compression
system into the vehicle, reduced refrigerant charge amount, parts
reduction, improved system controllability/stability, improved
efficiency, and improved system durability. Improved packaging and
refrigerant charge amount reduction is the result of a reduction in
overall tubing or line length. Parts reduction is achieved through
the replacing of a separate heat exchanger (comprised of heat
exchangers 6, 14 and evaporator 46) with a single integrated
component (i.e. the evaporator unit 60). Improved system
controllability/stability is the result of controlling the
superheat at locations where the refrigerant has already passed
through internal heat exchanger 64 instead of location 12 (depicted
in FIG. 19). TXV 42 or 8 (depicted in FIG. 19) meters refrigerant
flow more stably when the refrigerant entering it (exiting 48 or
10) has a minimum level of superheat. In the present disclosure, a
minimum level of superheat is maintained. However, it can be
difficult to achieve this minimum level of superheat in the state
of the art since the TXV is often operated very close to the point
of refrigerant saturation to maximize the performance through heat
exchangers 14, 6. Improved efficiency is also achieved in the
present disclosure by controlling the superheat of the refrigerant
leaving internal heat exchanger 64. This directly controls the
quality of the refrigerant entering compressor 28 and allows for
the user to tune the TXV to operate at the optimal point for
efficiency. This is contrary to the state of the art where the TXV
controls the superheat of the refrigerant entering the internal
heat exchanger 64. In the state of the art, the superheat of the
refrigerant leaving internal heat exchanger 64 is unknown, meaning
that the quality of the refrigerant returning to the compressor is
not known. Therefore, the system cannot be fully optimized for
efficiency. Improved durability is also derived from this fact. If
the quality of the refrigerant leaving the internal heat exchanger
64 is not known, then the system may allow refrigerant with not
enough superheat or refrigerant with too much superheat to return
to the compressor 28. This would result in either liquid
refrigerant returning to the compressor 28 or refrigerant that is
too hot (too much superheat) returning to the compressor 28. Both
of these scenarios result in reduced compressor 28 life and can
lead to premature failure of the system shown in FIG. 19.
[0038] With reference to FIG. 6, high pressure flow passage 38
(i.e. combination of the micro-channel tubes 70-76) may have a
combined free flow area in the range of but not limited to 20
mm.sup.2-85 mm.sup.2. Low pressure flow passage 48 (i.e. the
micro-channel tubes 90, 92, 94) may have a combined free flow area
in the rage of, but not limited to, 140 mm.sup.2-420 mm.sup.2.
Stated differently, the ratio of free-flow areas should be between
1.6-21.0 for the free-flow area of tubes 90-94 relative to the
free-flow area of tubes 70-76.
[0039] FIG. 7 is a graphical representation a Pressure (MPa) versus
Enthalpy (kJ/Kg) versus Temperature (Celsius) that demonstrates an
advantage of evaporator unit 60. With reference first to FIG. 2,
various stages throughout vapor compression cycle 24 are indicated.
For instance, reference numeral 100 of FIG. 2 represents a position
immediately after compressor 28 and corresponds to position 100 of
FIG. 7 which depicts a superheat or vapor region of vapor
compression cycle 24. Reference numeral 102 of FIG. 2 represents a
position immediately after condenser 32 and corresponds to position
102 of FIG. 7 which depicts a sub-cooled, liquid region of vapor
compression cycle 24. Reference numeral 104 of FIG. 2 represents a
position immediately after heat exchanger 38 and corresponds to
position 104 of FIG. 7 which depicts a further sub-cooled, liquid
region of vapor compression cycle 24. Reference numeral 106 of FIG.
2 represents a position immediately after TXV 42 and corresponds to
position 106 of FIG. 7 which depicts a dual phase region of liquid
and vapor of vapor compression cycle 24. Reference numeral 108 of
FIG. 2 represents a position immediately after heat exchanger 48
and corresponds to position 108 of FIG. 7 which depicts a
superheated or vapor region of vapor compression cycle 24.
[0040] FIG. 8 shows an evaporator unit 210 according to the second
embodiment. The difference between the first embodiment and the
second embodiment may be evaporator unit 210. The remaining
components may be the same as the first embodiment described
above.
[0041] Evaporator unit 210 may employ evaporator 211, internal heat
exchanger 212 and TXV 213. Evaporator 211, internal heat exchanger
212 and TXV 213 may be attached to each other to constitute an
integrated unit.
[0042] Evaporator 211 may employ a first tank 214, a second tank
215 and a plurality of tubes 216. First tank 214 may be provided
with both an inlet 217 of evaporator 211 and an outlet 218 of
evaporator 211. In this embodiment, first tank 214 may be disposed
in the upper side of evaporator 211. First tank 214 and second tank
215 may be connected to each other by the plurality of tubes 216.
There may be corrugate fins 219 between tubes 216. Tubes 216 and
corrugate fins 219 may define heat exchange core 220. Heat exchange
core 220 may have air gaps 221 that air passes through. Heat
exchange core 220 may be composed by stacking tubes 216 and
corrugate fins 219. So, when the refrigerant passes through tubes
216, the refrigerant exchanges heat with the air passing through
the air gap 221.
[0043] In this embodiment, first tank 214 may be divided into at
least two parts. One part is connected to inlet 217 of evaporator
211. The other part may be connected to outlet 218 of evaporator
211. Both parts may communicate with corresponding tubes 216 for
distributing the refrigerant to, and collecting the refrigerant
from, the corresponding tubes 216.
[0044] Second tank 215 forms U-turn portions 222, 223 of the
refrigerant flow pass, which lead the refrigerant from inlet 217 of
evaporator 211 to outlet 218 of evaporator 211.
[0045] More specifically, first tank 214 may be divided into three
parts. Each part may be connected to corresponding tubes 216. On
the other hand, second tank 215 may be divided into two parts in
this embodiment.
[0046] First part 224 of first tank 214 communicates with inlet 217
of evaporator 211. Then, first part 224 of first tank 214 may
distribute the refrigerant to corresponding tubes 216 (first tubes
225), which may be connected to first part 226 of second tank 215.
The refrigerant flowing into first part 226 of second tank 215 may
be distributed to tubes 216 (second tubes 227), which may be
connected to second part 228 of first tank 214. The refrigerant
flowing into second part 228 of first tank 214 may be distributed
to tubes 216 (third tubes 229), which may be connected to second
part 230 of second tank 215. The refrigerant flowing into second
part 230 of second tank 215 may be distributed to tubes 216 (fourth
tubes 231), which may be connected to third part 232 of first tank
214. The refrigerant flowing into the third part 232 of first tank
214 may lead to outlet 218 of evaporator 211.
[0047] In this embodiment, first part 226 and second part 230 of
second tank 215 provide U-turn portions 222, 223 of the refrigerant
flow pass. Also, second part 228 of first tank 214 provides another
U-turn portion of the refrigerant flow pass.
[0048] First part 224 of first tank 214 may be disposed next to the
third part 232 of first tank 214. Inlet 217 and outlet 218 of
evaporator 211 may face the same side of first tank 214. As a
result, the refrigerant flow passage is provided in the arrow
direction depicted in FIG. 8.
[0049] Evaporator 211 may further employ side walls 233, 234, which
may be disposed to or at the stacking end portion of said heat
exchange core 220. Side wall 233 has a mounting portion 235, to
which internal heat exchanger 212 may be attached.
[0050] Internal heat exchanger 212 may employ first connecting tank
236, second connecting tank 237, a high pressure flow passage 239,
and low pressure flow passage 240.
[0051] First connecting tank 236 may have a multi-level,
multi-floor structure similar to a two story building structure.
First floor 238 of first connecting tank 236 has a low pressure
refrigerant outlet 241 of internal heat exchanger 212, and second
floor 242 of first connecting tank 236 may have a high pressure
refrigerant inlet 243 of internal heat exchanger 212.
[0052] Second connecting tank 237 may also have a multi-level,
multi-floor structure similar to a two story building structure.
First floor 244 of second connecting tank 237 may have a low
pressure refrigerant inlet 245 as part of internal heat exchanger
212, and second floor 246 of second connecting tank 237 may have a
high pressure refrigerant outlet 247 as part of internal heat
exchanger 212.
[0053] High pressure flow passage 239 and low pressure flow passage
240 are stacked together, and enabled to exchange heat between high
pressure refrigerant and low pressure refrigerant therein. In this
embodiment, each length of high pressure flow passage 239 and each
length of low pressure flow passage 240 may be the same and high
pressure flow passage 239 and low pressure flow passage 240 may be
shifted or exchanged with each other with regard to a refrigerant
flow direction.
[0054] High pressure flow passage 239 connecting second floor 242
of first connecting tank 236 and second floor 246 of second
connecting tank 237. High pressure flow passage 239 penetrates
first floor 244 of second connecting tank 237.
[0055] Low pressure flow passage 240 connects first floor 238 of
first connecting tank 236 and the first floor of second connecting
tank 237. The low pressure flow passage 240 penetrates second floor
242 of first connecting tank 236.
[0056] Outlet 218 of evaporator 211 may be connected to low
pressure refrigerant inlet 245 of internal heat exchanger 212 via a
third connecting tank 259. Inlet 217 of evaporator 211 may be
connected to high pressure refrigerant outlet 247 of internal heat
exchanger 212 via TXV 213.
[0057] TXV 213 may employ housing portion 248 accommodating an
orifice portion 254 (depicted in FIG. 9), an operating portion 249
accommodating a diaphragm 258 (depicted in FIG. 9) connected to the
orifice portion 254, and temperature detecting element 250
detecting the temperature of the refrigerant.
[0058] In this embodiment, temperature detecting element 250 may
detect the temperature of the refrigerant flowing out from high
pressure refrigerant outlet 247 of internal heat exchanger 212. TXV
213 may further employ a connection pipe 251 connecting temperature
detecting element 250 and operating portion 249. Connection pipe
251 may lead inside pressure of temperature detecting element 250
to operating portion 249. Connection pipe 251 may be thermally
insulated from internal heat exchanger 212 by air gap defined
between connection pipe 251 and high and low pressure flow passages
239, 240.
[0059] FIG. 9 is a side cross sectional view of internal heat
exchanger 212 and TXV 213 in the second embodiment, as seen from a
side opposite evaporator side. TXV 213 is located on the upper
surface of internal heat exchanger 212. TXV 213 may employ a
housing portion 248, an operating portion 249 and a temperature
detecting element 250. Housing portion 248 has an inlet hole 252
communicating with outlet 253 of TXV 213 via an orifice portion
254. Orifice portion 254 may employ a valve seat 255 and ball
shaped valve 256. Ball shaped valve 256 may be operated by
operating rod 257. Operating rod 257 may be connected to and may be
actuated by a diaphragm 258. Diaphragm 258 is accommodated in
operating portion 249, and operating portion 249 actuates operating
rod 257 based on the temperature detected by temperature detecting
element 250. In this embodiment, internal heat exchanger 212 is
connected to outlet 218 of evaporator 211 via a third connecting
tank 259. Third connecting tank 259 is disposed next to second
connecting tank 237 and housing portion 248 of TXV 213. Inlet 265
of third connecting tank 259 is connected to outlet 218 of
evaporator 211. In this embodiment, internal heat exchanger 212 may
be provided with a certain structure described above, which can
divide different temperature, two-flow passages, each into a
plurality of smaller fluid passages. Such a structure may enable
the plurality of smaller fluid passages to exchange their heat
having different temperatures with each other. Then, the structure
may gather or combine the same kinds of fluid passages into one
original flow passage.
[0060] In this embodiment, evaporator 211 defines the refrigerant
flow passage (depicted in FIG. 8), inlet port 217 and outlet port
218 of evaporator 211. Internal heat exchanger 212 defines high
pressure flow passage 239, into which relatively high pressure
refrigerant flows, and low pressure flow passage 240, into which
low pressure refrigerant from outlet port 218 of evaporator 211
flows. Expansion device 213 may be connected to a downstream side
of high pressure flow passage 239 of internal heat exchanger 212
and upstream side of the inlet port 217 of evaporator 211. Internal
heat exchanger 212 may be attached to evaporator 211 to comprise
evaporator unit 210.
[0061] According to the above structure, evaporator unit 210 allows
the vapor compression cycle to use the cooling capacity of the
refrigerant flowing out from evaporator 211 as much as possible.
So, with evaporator unit 210 in this embodiment, total efficiency
of the vapor compression cycle is improved.
[0062] Also in this embodiment, evaporator 211 may employ a first
tank 214, a second tank 215, and a plurality of tubes 216 which
interconnect first tank 214 and second tank 215. The plurality of
tubes 216 define a heat exchange surface 260 along their
longitudinal side. Internal heat exchanger 212 may be attached to a
side surface 261 of evaporator 211. Side surface 261 may be
perpendicular to the heat exchange surface 260. Internal heat
exchanger 212 may reside over both first tank 214 and second tank
215.
[0063] According to the above structure, evaporator unit 210
disposes internal heat exchanger 212 to one of side surfaces where
first tank 214 or second tank 215 are not disposed. So, with
evaporator unit 210 in this embodiment, the heat exchange surface
is located near a center of evaporator unit 210 and that allows
evaporator unit 210 to be used in various kinds of refrigeration
cycles and improve its packaging.
[0064] Also in this embodiment, both inlet port 217 and outlet port
218 of the refrigerant flow passage defined by evaporator 211 are
disposed to the same side surface 261 of evaporator 211. So, with
evaporator unit 210 in this embodiment, internal heat exchanger 212
can connect both inlet port 217 and outlet port 218 at once.
[0065] Also, in this embodiment, inlet port 217 and outlet port 218
are both disposed to or in first tank 214. So, with evaporator unit
210 in this embodiment, heat exchanger 212 allows its high pressure
side flow direction in high pressure flow passage 239 to be
opposite from its low pressure side flow direction in low pressure
flow passage 245.
[0066] Also in this embodiment, expansion device 213 is a
thermostatic expansion device 213 (TXV 213) having temperature
sensing element 250 and diaphragm 258. Temperature sensing element
250 is attached to outlet 241 of low pressure flow passage 240 of
internal heat exchanger 212 or attached to a pipe 262 extending
from outlet 241 of low pressure flow passage 240 of internal heat
exchanger 212. So, with evaporator unit 210 in this embodiment,
evaporator unit 210 allows the vapor compression cycle to control
the super heat of refrigerant after passing through internal heat
exchanger 212 and before being drawn into compressor 28. So, with
evaporator unit 210 in this embodiment, the system durability can
be improved.
[0067] Also in this embodiment, thermostatic expansion valve 213
has connection pipe 251 which is means for connecting temperature
detecting element 250 and a chamber accommodating diaphragm 258.
Bracket 263 may insulate heat between internal heat exchanger 212
and connection pipe 251. So, with evaporator unit 210 in this
embodiment, the amount of heat exchange between internal heat
exchanger 212 and connection pipe 251 is reduced. That means
thermal expansion device 213 can detect the intended refrigerant
temperature more correctly.
[0068] Also in this embodiment, second connecting tank 237 is
divided into a first connecting space (more specifically, in this
embodiment first floor 244 of second connecting tank 237) and a
second connecting space (more specifically, in this embodiment
second floor 246 of second connecting tank 237) by a division wall
264. First connecting space 244 communicates with low pressure flow
passage 240, and second connecting space 246 communicates with high
pressure flow passage 239. At least one of high pressure flow
passage 239 and low pressure flow passage 240 (more specifically,
in this embodiment high pressure flow passage 239) penetrates the
other's connecting space 244 and the division wall 264 to reach its
respective connecting space 246. So, with evaporator unit 210 in
this embodiment, internal heat exchanger 212 allows two kinds of
fluid passages to connect a respective tank. The respective tank
may adjoin each other, and the fluid passages may reside in the
adjoining direction.
[0069] In other words, heat exchanger (more specifically, in this
embodiment internal heat exchanger 212) may employ a first
refrigerant flow passage (more specifically, in this embodiment low
pressure flow passage 240), a second refrigerant flow passage (more
specifically, in this embodiment high pressure flow passage 239)
disposed adjacent to first refrigerant flow passage 240, a
connecting tank (more specifically, in this embodiment second
connecting tank 237) which is divided into a first connecting space
(more specifically, in this embodiment first floor 244 of second
connecting tank 237) and a second connecting space (more
specifically, in this embodiment second floor 246 of second
connecting tank 237). First connecting tank space 244 communicates
with first refrigerant flow passage 240. Second connecting tank
space 246 communicates with second refrigerant flow passage 239.
Second refrigerant flow passage 239 penetrates first connecting
space 244 and division wall 264 to reach second connecting space
246.
[0070] So, heat exchanger 212 allows two kinds of fluid passages
(i.e. first refrigerant flow passage 240 and second refrigerant
flow passage 239) to connect respective tank (i.e. first floor 244
and second floor 246 of second connecting tank 237). The respective
tank 244 and 246 adjoin, and fluid passages 239, 240 are residing
in the adjoining direction.
[0071] FIG. 10 shows the exploded view of evaporator unit 300 in
the third embodiment. One difference between this embodiment and
the second embodiment is a position of a third connecting tank.
[0072] In this embodiment, third connecting tank 301 may be
disposed between housing portion 302 of TXV 303 and outlet 218 of
evaporator 211 (i.e. first tank 214 of evaporator 211).
[0073] Third tank 301 is disposed next to first floor 244 of second
connecting tank 237 and also next to TXV 303. Third tank 301
provides the flow passage between outlet 218 of evaporator 211 and
first floor 244 of second connecting tank 237.
[0074] In this embodiment, housing portion 302 of TXV 303 is
L-shaped. The L shape provides connecting passage 304 to inlet 217
of evaporator 211.
[0075] FIG. 11 shows the side cross sectional view of internal heat
exchanger 212 and TXV 303 in this embodiment, as seen from a side
opposite evaporator 211. The remaining components may be the same
as the first embodiment and the second embodiment.
[0076] FIG. 12 shows a side view of internal heat exchanger 212 and
TXV 303, as seen from the side where evaporator 211 is
disposed.
[0077] FIG. 13 shows the front view of evaporator unit 300 in the
third embodiment. In this embodiment, there is a heat insulating
gap 305 defined between side wall 233 of evaporator 211 and
internal heat exchanger 212. Gap 305 prevents internal heat
exchanger 212 from exchanging its heat with evaporator 211.
[0078] In this embodiment, first connecting tank 236 of internal
heat exchanger 212 and second tank 215 of evaporator 211 are
connected by fixing portion 306. The width of third connecting tank
301 and fixing portion 306 defines heat insulating gap 305. With
heat insulating gap 305, evaporator unit 300 allows the vapor
compression cycle to use the cooling capacity of the refrigerant
flowing out from evaporator 211 as much as possible.
[0079] Like components relative to the first embodiment and the
second embodiment are indicated by like reference numerals. Like
components have the same or nearly the same effects.
[0080] FIG. 14 shows the side cross-sectional view of internal heat
exchanger 212 and TXV 400 in a fourth embodiment, as seen from a
side opposite evaporator 211.
[0081] In this embodiment, internal heat exchanger 212 may be
connected to outlet 218 of evaporator 211 via Box-type TXV 400 and
third connecting tank 402. Housing portion 401 of TXV 400
accommodates the temperature detecting function (i.e. Box-type
TXV). Box-type TXV 400 detects the temperature of refrigerant
exiting from evaporator 211 via connecting rod 257. Inlet 403 of
third connecting tank 402 is connected to low pressure outlet 404
of Box-type TXV 400. Connecting rod 257 is disposed in low pressure
refrigerant passage 405 which connects outlet 218 of evaporator 211
and inlet 403 of third connecting tank 402. In this embodiment,
Box-type TXV 400 cannot detect the temperature of the refrigerant
exiting from outlet 241 of internal heat exchanger 212, but it
could eliminate communication pipe 251 and its clamp 263 described
above.
[0082] Internal heat exchanger 212 may be attached to evaporator
211. The remaining components may be the same as the other
embodiments described above and may have the same or similar
effect. Like components relative to the embodiments described
above, are indicated by like reference numerals.
[0083] FIG. 15 shows the side cross sectional view of internal heat
exchanger 212 and TXV 400 in a fifth embodiment, as seen from a
side opposite evaporator 211. In the fourth embodiment, high
pressure flow passages 239 and low pressure flow passages 240 are
the same length.
[0084] But in the fifth embodiment, high pressure flow passages 500
and low pressure flow passages 501 are not the same length. High
pressure flow passages 500 are longer than low pressure flow
passages 501. High pressure flow passages 500 penetrate both
division walls 264 of first connecting tank 236 and second
connecting tank 237.
[0085] First connecting tank 502 of this embodiment is different
from other embodiments. First floor 503 of first connecting tank
502 has a high pressure refrigerant inlet 505 of internal heat
exchanger 212. Second floor 504 of first connecting tank 502 has a
low pressure outlet 506 of internal heat exchanger 212.
[0086] Internal heat exchanger 212 may be attached to evaporator
211. The remaining components may be the same as the fourth
embodiment and may have the same effect. Like components relative
to the embodiments described above, are indicated by like reference
numerals.
[0087] FIG. 16 shows an exploded view of evaporator unit 600 in
sixth embodiment. Evaporator 601 in the sixth embodiment differs
from evaporator 211 described in the other embodiments.
[0088] In this embodiment, evaporator 601 comprises distribution
tank 602 and collecting tank 603. Tubes 604 connect distribution
tank 602 and collection tank 603. Distribution tank 602 has an
inlet port 605 of the evaporator. Collecting tank 603 has an outlet
port 606 of evaporator 600.
[0089] Internal heat exchanger 212 in this embodiment has a similar
structure as that of the fourth embodiment, but the position of low
pressure refrigerant outlet 607 of internal heat exchanger 212 is
different from the position of low pressure refrigerant outlet 241
of internal heat exchanger 212 of the fourth embodiment.
[0090] Also, the flow direction of the low pressure refrigerant
flow of internal heat exchanger 212 is opposite from the fourth
embodiment, because of a difference in the evaporator
structure.
[0091] The low pressure refrigerant exiting from evaporator 600
goes into first floor 238 of first connecting tank 236 from low
pressure inlet 608. Low pressure outlet 607 of internal heat
exchanger 212 is disposed at first floor 244 of second connecting
tank 237. The low pressure refrigerant exiting from outlet 607
passes through Box-type TXV 400 and exits from outlet 609 of
Box-type TXV 400. Thus, the direction of flow through low pressure
refrigerant flow passage 240 is the same as the flow direction of
high pressure refrigerant flow passage 239. In this embodiment,
Box-type TXV 400 can detect the temperature of the refrigerant
which passed through internal heat exchanger 212.
[0092] FIG. 17 shows a side cross sectional view of internal heat
exchanger 212 and TXV 400 in the sixth embodiment, as seen from a
side opposite evaporator 600.
[0093] Internal heat exchanger 212 may be attached to evaporator
600. Like components may be the same as in the fourth embodiment,
and may have the same effects. Like components are indicated by
like reference numerals.
[0094] FIG. 18 shows an exploded view of evaporator unit 300 in the
seventh embodiment. One difference between this embodiment and the
second embodiment is the type of expansion device employed.
[0095] In this embodiment, the expansion device may be an
electronic expansion valve 700, which may be controlled by
electronic control unit 701. Electronic control unit 701 may
control an opening degree of electronic expansion valve 700 based
on the calculated super heat degree of the refrigerant flowing into
the compressor or flowing out of evaporator unit 300.
[0096] The super heat degree is calculated based on the temperature
of the low pressure side refrigerant. The temperature of the low
pressure side refrigerant is detected by a temperature sensor 702.
The temperature sensor may be disposed in at least one of outlet
241, pipe 262 or fins 219.
[0097] Electronic control unit 701 may use the refrigerant flow
rate in the refrigerant cycle to estimate the super heat degree.
The refrigerant flow rate is detected by a refrigerant flow rate
sensor 703, which may be disposed in the outlet side of the
compressor.
[0098] The foregoing description of the embodiments has been
provided for purposes of illustration and description. It is not
intended to be exhaustive or to limit the invention. Individual
elements or features of a particular embodiment are generally not
limited to that particular embodiment, but, where applicable, are
interchangeable and can be used in a selected embodiment, even if
not specifically shown or described. The same may also be varied in
many ways. Such variations are not to be regarded as a departure
from the invention, and all such modifications are intended to be
included within the scope of the invention.
[0099] Example embodiments are provided so that this disclosure
will be thorough, and will fully convey the scope to those who are
skilled in the art. Numerous specific details are set forth such as
examples of specific components, devices, and methods, to provide a
thorough understanding of embodiments of the present disclosure. It
will be apparent to those skilled in the art that specific details
need not be employed, that example embodiments may be embodied in
many different forms and that neither should be construed to limit
the scope of the disclosure. In some example embodiments,
well-known processes, well-known device structures, and well-known
technologies are not described in detail.
[0100] The terminology used herein is for the purpose of describing
particular example embodiments only and is not intended to be
limiting. As used herein, the singular forms "a," "an," and "the"
may be intended to include the plural forms as well, unless the
context clearly indicates otherwise. The terms "comprises,"
"comprising," "including," and "having," are inclusive and
therefore specify the presence of stated features, integers, steps,
operations, elements, and/or components, but do not preclude the
presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof. The
method steps, processes, and operations described herein are not to
be construed as necessarily requiring their performance in the
particular order discussed or illustrated, unless specifically
identified as an order of performance. It is also to be understood
that additional or alternative steps may be employed.
[0101] When an element or layer is referred to as being "on,"
"engaged to," "connected to," or "coupled to" another element or
layer, it may be directly on, engaged, connected or coupled to the
other element or layer, or intervening elements or layers may be
present. In contrast, when an element is referred to as being
"directly on," "directly engaged to," "directly connected to," or
"directly coupled to" another element or layer, there may be no
intervening elements or layers present. Other words used to
describe the relationship between elements should be interpreted in
a like fashion (e.g., "between" versus "directly between,"
"adjacent" versus "directly adjacent," etc.). As used herein, the
term "and/or" includes any and all combinations of one or more of
the associated listed items.
[0102] Although the terms first, second, third, etc. may be used
herein to describe various elements, components, regions, layers
and/or sections, these elements, components, regions, layers and/or
sections should not be limited by these terms. These terms may be
only used to distinguish one element, component, region, layer or
section from another region, layer or section. Terms such as
"first," "second," and other numerical terms when used herein do
not imply a sequence or order unless clearly indicated by the
context. Thus, a first element, component, region, layer or section
discussed below could be termed a second element, component,
region, layer or section without departing from the teachings of
the example embodiments.
[0103] Spatially relative terms, such as "inner," "outer,"
"beneath," "below," "lower," "above," "upper," and the like, may be
used herein for ease of description to describe one element or
feature's relationship to another element(s) or feature(s) as
illustrated in the Figures. Spatially relative terms may be
intended to encompass different orientations of the device in use
or operation in addition to the orientation depicted in the
Figures. For example, if the device in the Figures is turned over,
elements described as "below" or "beneath" other elements or
features would then be oriented "above" the other elements or
features. Thus, the example term "below" can encompass both an
orientation of above and below. The device may be otherwise
oriented (rotated 90 degrees or at other orientations) and the
spatially relative descriptors used herein interpreted
accordingly.
* * * * *